Solution deposition approach to high J_C coated conductor fabrication

Great strides have been made in YBCO coated conductor fabrication using the RABiTS approach in the past few years and critical current densities (J _c) of over 3 MA/cm² on 10 meter long tapes have been achieved. Solution deposition for buffer layer processing has the potential to reduce the process complexity and make the conductor fabrication more cost-effective. In our work, we have demonstrated that several of the standard buffer layers can be replaced by sol-gel processed lanthanum zirconium oxide (LZO) layer. A J_c of about 2 MA/cm² has been demonstrated on LZO films for pulsed laser deposited YBCO and J_c up to 1.5 MA/cm² have been demonstrated for MOD-YBCO using a sputtered CeO ₂ cap layer on the sol-gel LZO films. Solution processed buffer layers have been found to have rapid growth kinetics which could potentially mean high rate processing of these buffer layers. Using simulated ex-situ YBCO annealing studies, it has been determined that the performance of 80-120 nm thick LZO films is comparable to the standard 3-layer vapor deposited CeO ₂/YSZ/Y₂O₃ buffer stack. Using a 120 nm thick LZO layers on NiW substrates, in collaboration with American Superconductor Corp., all-solution coated conductors with the stacking sequence MOD-YBCO/Solution CeO₂/Solution LZO/NiW, critical currents of up to 140 A/cm has been measured. Such high critical currents on an all-solution conductor offers promise for cost-effective scale-up of coated conductor processing.